Are Young Teams More Likely to Fade After Hot Starts?

Heading into the 2018 season, the NL East picture appeared to be pretty clear. The Washington Nationals — while having just one more year of Bryce Harper — entered the campaign as presumptive favorites. The Mets, despite possessing a talented roster, were conducting their affairs in an all-too-familiar way, while the Marlins were conducting their affairs in a way that made their roster much less talented.

In Atlanta and Philadelphia, meanwhile, the future was on the horizon. The Braves boasted a stable of young arms, Freddie Freeman, and the best prospect in the game (mon-Ohtani division). The Phillies supplemented their equally impressive young core with the signing of Jake Arrieta, announcing that they were ready to end the rebuild and begin contending. It only seemed a matter of time before the division would be theirs.

A couple months into the season, the picture is somewhat less clear. Indeed, it seems as though the future has arrived a little early in the NL East. As of this morning, the Braves sit atop the NL East at 35-25, with the Phillies just a couple games behind in third. (The Nationals sit in second.) The two teams have gone about things in different ways: where the Braves — led by Ozzie Albies, the aforementioned Freeman, and a surprising Nick Markakis — boast a top-five offense, the Phillies have benefited from a top-five pitching staff.

Whenever a young team makes this sort of run, it’s inevitably accompanied by discussions concerning the importance of experience. Experience, so it is said, leads to more staying power over the course of a long season or playoff run. Young teams are then expected to fade or fall short, thus earning some “much needed experience” and checking off that box on their development path.

The thing is, baseball is getting younger, at least on the batting side of things. With aging curves having changed since the height of the so-called Steroid Era, we’ve seen the average age for hitters (weighted by plate appearances) decrease from 29.15 in 2001 to 28.74 in 2011 to 28.29 last year. So, as teams get younger, it seems likely that we’ll see more “young” teams contending for playoff spots, or even World Series titles.

With this in mind, what can we expect from young teams that get off to hot starts in the year 2018? Teams like the Braves and Phillies this year? Do these teams fade, or are they able to hold on?

The Braves and Phillies both have an average age for hitters (weighted by plate appearances) and pitchers (weighted by total batters faced) younger than 28 years. This is not exactly uncommon, as it has happened a total of 82 times over the course of a season since 2002. What’s rarer is that only 18 of these teams have produced a winning percentage of at least .525 through June 1st of that year.

This 2018 Phillies, whose hitters and pitchers average less than 27 years, join an even rarer group. Only the 2008 Rays saw as good of a record out of so young a team. Of course that Rays team made it to the World Series that season (to be beaten by the Phillies), becoming one of five teams from this group (along with the 2010 Rays, 2012 Nationals, 2012 Orioles, and 2013 Braves) to make the playoffs. This isn’t always the case, though, as these young teams tend come back to earth as the season goes along.

Of these 18 teams, only three of them (2012 Orioles, 2012 Nationals, 2013 Braves) maintained or improved on their June 1st win percentage, with a group average change of -0.056. However, it’s not like all these teams fell apart, as 12 of the 18 finished the season at .500 or above.

Is this any different from “experienced” teams? Looking at club that featured both an average hitter and pitcher age (weighted as before) is over 28 yields 120 teams with a win percentage of at least .525 on June 1st. Of these teams, 38 of them maintained or improved on their June 1st win percentage, with a group average difference between end of year win percentage and June 1st win percentage of -0.027. Within these teams, 104 of the 120 teams finished at .500 or better. So, while “experienced” teams also fall back from hot starts, they don’t seem to fall as far as the younger teams.

Why is this? Do young teams truly lack the experience necessary to stay in the race? Do they experience regression to the league mean? There doesn’t seem to be a clear-cut explanation there. If we look at the league average FIP or wOBA, we see all combinations of teams exceeding FIP or wOBA by all manners of margins and still see their final win percentage falling above or well below where they stood on June 1st with no particular pattern.

Maybe it’s that teams regress to their true talent? If we take projections (using Steamer) as the best preseason guess of true talent, we have only five data points from which to work, nowhere near enough to draw any conclusions. Even amongst these five points, we don’t see even the vaguest of extrapolations about what drives this downfall.

Fans of these teams may be content merely with improvement, believing that even if this season represents a checkbox on the way to title contention; however, this isn’t always the case. Yes, the Orioles’ back-to-back appearances on this list in 2012-2013 set up a run from 2012 to -16 that resulted in three playoff appearances and the most wins in the American League over that time. The Rays’ youth set up their impressive run from 2008 to 2013, with a World Series trip and four playoff appearances. Yet, at the same time, an Indians clubs built on youth in 2011-2012 produced just a single playoff appearance and general mediocrity until 2016. And hitting closest to home, the young Braves of 2013 won their division, came out of the gate strong but finished poorly in 2014, then bottomed out in 2015 and 2016 to to set up their current run. No matter the promise of youth or the possibility of being “ahead of schedule,” future success just isn’t guaranteed.

So will the Braves and Phillies stay in the playoff race, or even at least manage to stay above .500? It’s honestly hard to say. Past teams in this situation offer very little guidance, only suggesting that, on the average, these young teams are likely to come back towards .500, seemingly at a higher rate than more experienced teams. Maybe one or both of these teams can play off their strengths to not only avoid a regression to .500 but build off that success to long-term success in future seasons. But this is far from a certainty, and something we will just have to monitor as the season goes forward.